Anisotropic mechanical and tribological properties of SiAlON matrix composites containing different types of GNPs

SiAlONs can have new application areas by increasing their lifetime and durability if their mechanical and tribological properties are improved. Even though the properties of the matrix improve with GNPs addition, the differences in GNPs properties lead to different property values. In this study, four different GNPs having different surface area, lateral dimension, thickness, and aspect ratio were added to SiAlON and composites were sintered by using SPS. The effects of these different properties on fracture toughness and friction coefficient of SiAlONs were investigated. GNPs, which have the high surface area, lateral dimension, aspect ratio and low thickness, provided the highest fracture toughness and best friction coefficient performance to SiAlON. The fracture toughness of composites were generally higher in the in-plane direction compared to through-plane direction due to GNPs orientation. Conversely, the friction coefficient and hardness values measured higher in the through-plane direction than in the in-plane direction.